Have a desk job? Don’t do much more for fitness than ride your bike a few times a week? You’re at high risk of developing back pain, obesity, diabetes and cancer. The average American spends 56 hours a week sitting, and even if you ride, that may not be enough.

The good news: Bicycling has the cure. Adding core, flexibility and high-impact exercises to your routine will help prevent the biomechanical imbalances common among cyclists, and will help keep you fit for life….